Iterative Reprojection Reconstruction algorithm with attenuation correction applied to truncated projections in SPECT

When SPECT sinograms are truncated, the Iterative Reprojection Reconstruction (IRR) algorithm based on the Radon transform cannot restore the distribution that would be obtained with the complete projection data set, even in the field of view taken as a region of interest. Nevertheless, when the attenuation characteristics are known and an attenuation correction is incorporated in the IRR scheme, the source distribution can be recovered in the field of view and, in the particular case of a contrasted attenuation map, even outside the region.